Effect of Dietary Energy Source and Free Choice Feeding on Performance of High Lean Pigs
The effects of dietary energy sources in corn on the growth responses and carcass composition of high lean pigs fed from 55 to 110 kg body weight were evaluated. Low fiber composite corns were created by replacing the fiber in normal corn with isocaloric amounts of either corn starch or corn oil. Feeding the low fiber, composite corns reduced the amount of feed required per unit of body weight compared with that of pigs fed the high fiber, normal corns. However, the daily body weight and muscle gains and efficiency of metabolizable energy (ME) utilization for body weight and muscle gain were similar among pigs fed the low and high fiber corns. Body composition (backfat, loin muscle area, and muscle mass) at 110 kg body weight also were similar among corn treatments. When given the choice between the normal and composite corns, pigs consumed more of the low fiber composite corn with added fat but not with added starch. The feed required per unit of gain also was reduced in pigs allowed free choice access to normal and composite corns compared with pigs self-fed the normal corns. Pig growth and body composition were not altered by free choice selection of normal and composite corns.